A novel prion strain is responsible for the first case of chronic wasting disease in Finnish moose

Concern is mounting over the global emergence, expanding host range, and uncertain zoonotic potential of chronic wasting disease (CWD), a fatal, infectious disease of cervids caused by prions. Our previous studies using genetically modified CWD-susceptible mice showed that Norwegian and North American CWD are caused by different prion strains. Here we investigated the properties of prions causing the first case of Finnish moose CWD. While Finnish and Norwegian moose CWD prions share characteristics that distinguish them from North American CWD including the inability to replicate in lymphoid tissues, common responses to variations at residue 226 of host prion protein, and overlapping central nervous system profiles, they also exhibit pronounced conformational variation which is consistent with strain differences between Finnish and Norwegian moose CWD. Our findings support the existence of a surprisingly diverse portfolio of emergent CWD strains in Nordic countries that is etiologically distinct from North American CWD. Summary linePrion strain properties from the first case of chronic wasting disease in a Finnish moose are similar but not identical to Norwegian cases, supporting a growing population of strains in Nordic countries.